Fin mount latch

ABSTRACT

The subject invention provides a latching mechanism particularly suitable for mounting a stabilizing fin on an external engine missile. Generally, the invention relates to spring-biased, camoperated latches and more particularly to a positive-locking latch device in which a circular-band spring biases locking pins into retaining holes in a fairing or shroud for locking a fin on a missile. The latch is released by rotating a cam actuator which contacts the locking pins and withdraws them from the retaining holes, when the fin may be removed from the missile.

ite States Patent Polk, if.

[ 51 Mar. 14, 1972 [54] FIN MOUNT LATCH [72] Inventor: Albert S. Polk,Jr., Baltimore, Md.

[73] Assignee: The Johns Hopkins University, Baltimore,

22 Filed: Dec. 30, 1969 21 App1.No.: 889,206

[52] US. Cl ..244/3.24

[56] References Cited UNITED STATES PATENTS 3,276,377 10/1966 Bell..244/3.24 3,228,335 1/1966 Thompson ..244/3.24

3,093,075 1/1963 Garrett et al. ..244/3.24

Primary ExaminerRobert F. Stahl Att0rney-Richard S. Sciascia, J. A.Cooke and R. J. Erickson [57] ABSTRACT The subject invention provides alatching mechanism particularly suitable for mounting a stabilizing finon an external engine missile. Generally, the invention relates tospring-biased, cam-operated latches and more particularly to apositivelocking latch device in which a circular-band spring biaseslocking pins into retaining holes in a fairing or shroud for locking afin on a missile. The latch is released by rotating a cam actuator whichcontacts the locking pins and withdraws them from the retaining holes,when the fin may be removed from the missile.

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PATENTEDHAR 14 I972 sum 5 OF 5 FIN MOUNT LATCH BACKGROUND AND BRIEFSUMMARY OF THE INVENTION Space restrictions imposed on various augmentedthrust missile designs have necessitated external engine geometrieswhich prevent the use of normal control surface attachment mechanisms.The present invention provides simple, effective means for attachingcontrol surface/actuator packages, with control surfaces thereon, to amissile having externally mounted engines. A saddle-type mounting isutilized which straddles each external engine. That is, a control boxfor each control surface forms a portion of the saddle mounting, saidmounting including legs which straddle portions of the engine and areattached to fairings or shrouds along the missile by double-acting,positive-locking latches.

Use of the present invention allows rapid and facile installation of acontrol surface package on a missile by one person with the use of but asimple spanner wrench.

The latch disclosed herein finds utility in any number of applications.Such a simple, easily operated, yet effective latching device canreadily be used with success as a car trunk latch, a tool cabinet latch,or a door lock.

It is therefore an object of the present invention to provide a latchfor mounting control surfaces and related actuating devices on a missileutilizing external engines.

It is also an object of the invention to provide a positivelocking latchcapable of providing rapid attachment of a stabilizing surface packageto a missile body.

A further object of the invention is to provide simple, effectivelatching means for attachment and detachment of a control package to andfrom a missile and which is readily operable by one person withoutspecial equipment.

A still further object of the invention is to provide easily operablelatching means which is also suitable for general use as a lock, catch,or stay.

Further objects and attendant advantages of the invention will becomemore readily apparent in the light of the following description of apreferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective of asaddle-type control surface mounting utilizing the double-acting,positive-locking latch of the present invention, the mounting beingshown prior to attachment to an external engine missile;

FIG. 2 is a side elevation of a portion of the aft section of anexternal engine missile showing a control surface surmounting one of theexternal engines and attached to the body of the missile by thedouble-acting, positive-locking latch of the present invention, thelatch being shown in broken lines;

FIG. 3 is a section, partly broken away, on the line 3-3 of FIG. 2;

FIG. 4 is an enlarged detail axial section of the latch of the presentinvention;

FIG. 5 is a plan view of the latch, shown in partial section and withthe latch pins extended, and

FIG. 6 is a view similar to FIG. 5 but showing the latch pins retracted.

DESCRIPTION OF THE PREFERRED EMBODIMENT Launcher size and storagerestrictions have required the development of external engine missilesfor thrust augmentation. Such a missile requires unique means forsuitably mounting control surfaces on its body. In FIG. 1, a controlsurface mounting unit is shown generally at 1, prior to its attachmentto the body 3 of a missile having externally mounted engines 5. As canbe seen in FIGS. 1, 2, and 3, the control surface mounting unit 1comprises a control fin 7 which is permanently mounted on a controlsurface actuator package 9, the package 9 having a saddle-like bodyportion 11 with spaced legs 11a. When fitted to the missile body 3, legs11a of the saddle-like body portion 11 straddle one of the externallymounted engines 5. The body portion 11 is intended to fit into a cutout13 in a raised engine fairing or shroud 15, the body portion 11 havinginclined surfaces 17 which fit flush against surfaces 19 of said shroud.

A latch 21 is disposed in each leg 11a of the body portion 11 and, in amanner to be more fully described hereinafter, secures the controlsurface mounting unit 1 to the shroud l5 and thus to the missile body 3.Latch pins 23 are seated in retaining holes 25 located in the shroud 15by a circular spring 27. Two of the latches 21, one located in each legof the body portion 11, are utilized for mounting each unit 1 on themissile body.

Installation of the actuator package 9 may be readily accomplished byone person. As the legs of the body portion 11 of the package 9 aremoved into the cutout portion 13, end walls 19 of the shroud 15 willengage the latch pins 23 of the latches 21 and bias them inwardly untilsaid pins confront the holes 25, when the pins will be urged into saidholes by the spring 27. The unit 1 will thus be mounted in the cutout 13with the legs of the portion 1 l flush with the walls of th shroud 15.

In FIGS. 2 and 3, the control surface mounting unit 1 is shown fastenedto the shroud 15 on the missile body 3. FIG. 3 particularly illustrateshow the unit straddles the engine 5 to locate the control fin 7 andactuator package 9 in non-obstructive relation with respect to saidengine.

The structure and operation of the latches 21 may be more clearlyunderstood by reference to FIGS. 4, and 6. Each latch 21 is comprised ofmating discs 31a and 3l-b, the two opposed latch pins 23, and thecircular spring 27 and is encased in one of the legs of the previouslydescribed saddle-like portions 1 l.

The latches 21 in the legs of the saddle-like portion 1 1 comprisehousings 22 which defme cam actuators rotatable in said legs forretracting their respective latch pins 23. The housings 22 are eachcomprised of a pair of the mating discs 31a and 31-b which have flatouter surfaces and elliptical recesses in their inner surfaces. Sincethe discs 31a and 3l-b are virtually identical, a detailed descriptionof one of them will suffice. Accordingly, as best seen in FIGS. 4 and 5,the recess in the disc 31a is bounded by a flange 35 which has acircular outer rim and an elliptical inner wall 32. A hub 37 is mountedin the center of the disc 31a and cooperates with a similar hub on thedisc 31-b, screws 45 being employed for retaining the discs incooperating relationship.

When joined as described above, the discs provide an enclosed ellipticalcavity 53 having an annular slot 54. The circular spring 27 is disposedwithin the enclosed cavity 53 and is of a diameter slightly smaller thanthe minor axis of said elliptical cavity.

The latch pins 23 are formed with spaced annular flanges 55 whichimpinge on the inner surfaces of cylindrical bores 57 formed in theportion 11, and with rounded outer ends which readily fit into theretaining holes 25 in the shroud 15, as shown in FIGS. 1 and 2.Corresponding inner end portions of the pins 23 extend through the slot54 into the elliptical cavity 53 and have enlarged heads 63 which havesliding engagement with the elliptical wall 32. Corresponding inner endfaces of the heads 63 contact the circular spring 27. Normally, thespring 27 maintains a circular configuration and simply retains the pins23 in engagement with the elliptical inner wall 32 of the cavity 53.However, as previously described, movement of the legs of the actuatorpackage 9 into position in the cutout portion 13 will increase pressureon the rounded outer ends 65 of the latch pins 23, causing them to movetoward each other in the bores 57 in the body portion 11 and to deformthe circular spring 27, thus causing said spring to exert a forceagainst said pins. As long as an external pressure greater than or equalto the force is exerted by the spring is maintained, the pins 23 willremain inside the bores 57. On release of such external pressure, aswhen the pins confront the retaining holes 25, said pins 23 will snapinto positions with their rounded ends 65 extending into said holes. Theunit 1 is thus mounted on the body of the missile.

llteferring particularly to FIG. 5. the disc 31a of the housing l2 hascircular sockets 67 disposed in its surface to receive the jlBWS of aspanner wrench (not shown) for detaching the unit 1 lrom the engine 5,the flat outer surface of the disc being flush with the exterior surfaceof the body portion 11. More specifically, when the jaws of a spannerare inserted in the sockets 67 Mid the housing 12 is rotated in eitherdirection. the elliptical walls 32 of the cavity 53 cam the enlargedheads 63 of pins 23 inwardly toward the center of the housing, therebydeforming the circular spring 27 and biasing the latch pins 23 to aposilllOn where the rounded ends 65 are drawn inside the bores 57 Illflthe body portion 11 and from the retaining holes 25 in the illl'llOUd15. In such position. the unit 1 may be lifted free of the ll'llSSllCbody. Removal of the tool allows the latch pins to be moved back totheir original positions. by action of the spring lll7. The unit 1 maybe easily remounted on the missile body, when desired, thus providingground testing of latching effectiveness.

The snap-action latch of the present invention [5 not limited to theenvironment described. The utility of this simple. yet efl'ectivelatching device causes it to be applicable to any number of usesrequiring a positive locking latch. For example. the latch could beeasily modified to provide a car trunk latch operable either by closureor the trunk door or by operaill.)

tie in the retaining holes for securing the control surface nountingunit on the engine.

it. The invention as recited in claim 1, wherein the latches eachinclude a housing rotatable in a leg,

and a spnng in the housing and urging the latch pins into engagement inthe retaining holes.

.3. The invention as recited in claim 2, wherein the housing has anelliptical wall and wherein the latch pins have heads engaging saidspring and said elliptical wall, whereby upon rotation of the housingsaid latch pins by cam action of the wall on the heads will be withdrawnfrom the retaining holes to permit withdrawal of the control surfacemounting unit from the eu- :out.

4. The invention as recited in claim 2, wherein the housing includes apair of mating discs having an elliptical wall defining an ellipticalcavity. and an annular slot communicating between the cavity and theexterior of the housing, said slot receiving corresponding inner endportions of the latch pins.

.5. In combination with a missile having an externally mounted engineand a shroud on the engine and having a eutout. said cutout having wallsformed with retaining holes,

.1 control surface mounting unit having an actuator package and acontrol fin and having a body portion with walls and toaced legs,

means for detachably mounting the control surface mounting unit in thecutout with the spaced legs straddling the mgine and the walls of saidunit engaging the walls of the uncut.

and means comprising a latch mounted in each of said legs,

each said latch comprising a housing, a pair of opposed tttch pins. anda spring in the housing and urging the latch ZilnS to engage in theretaining holes,

raid housing having a cam surface engageable with portions it the latchpins and being rotatable for disengaging end ."lOlIlOHS of said latchpins from the retaining holes.

inirvn

1. In combination with a missile having an externally mounted engine,and a shroud on the engine and having a cutout therein, a controlsurface mounting unit having a body portion with spaced legs, wallsdefining the cutout and having retaining holes therein, a latch in eachof the legs for detachably mounting the control surface mounting unit inthe cutout with the legs straddling the engine, and pins in the latchesand having end portions thereof engageable in the retaining holes forsecuring the control surface mounting unit on the engine.
 2. Theinvention as recited in claim 1, wherein the latches each include ahousing rotatable in a leg, and a spring in the housing and urging thelatch pins into engagement in the retaining holes.
 3. The invention asrecited in claim 2, wherein the housing has an elliptical wall andwherein the latch pins have heads engaging said spring and saidelliptical wall, whereby upon rotation of the housing said latch pins bycam action of the wall on the heads will be withdrawn from the retainingholes to permit withdrawal of the control surface mounting unit from thecutout.
 4. The invention as recited in claim 2, wherein the housingincludes a pair of mating discs having an elliptical wall defining anelliptical cavity, and an annular slot communicating between the cavityand the exterior Of the housing, said slot receiving corresponding innerend portions of the latch pins.
 5. In combination with a missile havingan externally mounted engine and a shroud on the engine and having acutout, said cutout having walls formed with retaining holes, a controlsurface mounting unit having an actuator package and a control fin andhaving a body portion with walls and spaced legs, means for detachablymounting the control surface mounting unit in the cutout with the spacedlegs straddling the engine and the walls of said unit engaging the wallsof the cutout, said means comprising a latch mounted in each of saidlegs, each said latch comprising a housing, a pair of opposed latchpins, and a spring in the housing and urging the latch pins to engage inthe retaining holes, said housing having a cam surface engageable withportions of the latch pins and being rotatable for disengaging endportions of said latch pins from the retaining holes.